A food chain is the natural sequence of how animals, micro-organisms, and plants get energy to preform there proposes. Food chains show how energy gets to one organism to the next. It starts with the Sun, a huge source of energy. Sun gives food to plants, which gives energy to the plant (I.E. producer, which is a category of consumers in an ecosystem.) Then, herbivores or omnivores eat the plant, transferring the energy to the consumer. For example, a dandelion is eaten by an insect. That insect is eaten by a bird. That bird can be eaten by another bird. Now, if that bird is high on a food chain, chances are that that will be the end until the bird drops dead. Now the decomposers can consume the dead bird, and that gives energy to the decomposer, and so on. Human beings are on the top, because usually no animals eat humans. Plus, were omnivores and we can eat a huge amount of energy (calories). http://en.wikipedia.org/wiki/Photosynthesis
Food Chains and Food Webs are somewhat the same. They both show how one organism would get energy from another organism. But they are different as well. Food chains show just one sequence. (above) Food Webs are a large, complex order that spans off in multipul directions. Basicly, food webs are a large jumble of food chains.
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